TB-Diabetes: A deadly marriage

Lung diseases are one of the most common medical conditions in the world. Millions of people suffer from lung complications that may cause diseases like asthma, chronic bronchitis, pneumonia, TB and lung cancer, among others. Smoking, air pollution and life style changes further exacerbate the problems, more so if they result in a deadly combination of communicable and non communicable diseases.
TB-diabetes is one such example of a public health challenge that is bound to become very serious unless immediate action is taken to prevent it. This is relevant also in the context of post-2015 sustainable development agenda, where one of the goals is to end the TB epidemic by 2030. This will not be easy in the absence to a response to TB-diabetes.

The World Health Organisation (WHO) reports that Zimbabwe has not been able to meet the Millennium Development Goal target of 50% reduction in TB prevalence and mortality rates, due to a significant increase in new infections in the past decade. Even though there has been some decrease in the prevalence rates of TB during this time at the global and domestic level, there has also been an alarming increase in the incidence of non-communicable diseases (NCDs), like diabetes, in the country. High prevalence of major risk factors leading to reactivation of TB were seen within the population, with diabetes being in the forefront. The Zimbabwe Diabetes Association estimates that 10 in every 100 people in Zimbabwe are living with diabetes.

Paul Jensen, Senior Policy Advisor at the International Union against Tuberculosis and Lung Disease (The Union) lists TB-diabetes as a public health challenge that will become more serious unless action is taken now to prevent it. “It is estimated that 15% of all people with TB worldwide also have diabetes. This comes out to be 1,042,000 adults who have TB and who are also living with diabetes. This is only slightly less than the number of people with TB who are living with HIV infection. What is worse is that diabetes prevalence is increasing globally and the number of people who are living with diabetes is predicted to increase by 50% by 2030”, Paul fears.

Links between diabetes and TB have been recognised for a long time. Diabetes is known to weakens one’s immune system making the body more vulnerable to TB. There is growing evidence that diabetes is an important risk factor for TB and might affect disease presentation and treatment response. Professor Anthony Harries of The Union recognizes that a person with diabetes is three times more likely to contract TB, which may lead to recurrent TB and liver toxicity, and even increase chances of death.

Yet, until recently, TB-diabetes was not taken seriously enough, perhaps because it was believed that in countries where TB is common, diabetes is not and vice versa. But the sad part is that diabetes is no longer a rich man’s disease. It is becoming increasingly common in low and middle income countries where TB is already highly endemic.

Even though TB incidence has seen a decline in high-income countries recently, incidence remains high in countries that have high rates of infection with HIV, high prevalence of malnutrition and crowded living conditions, or poor TB care and control infrastructure. At the same time, diabetes prevalence is soaring globally, fuelled by obesity. People with a weak immune system, as a result of chronic diseases such as diabetes, are at a higher risk of progressing from latent to active TB--is estimated that one in three people in the world is infected with latent TB that poses a lifelong risk of developing into active TB. At the same time, infectious diseases like TB complicate diabetes treatment.

A large proportion of people with diabetes as well as TB is either not diagnosed at all or diagnosed too late. Early diagnosis can help improve care and control of both. The WHO recommends that all people with TB should be screened for diabetes. Likewise screening for TB in people with diabetes should be considered, particularly in high TB prevalence settings. Also WHO-recommended treatments should be rigorously implemented for people with TB-diabetes, more so because they have a higher risk of mortality during TB treatment and of TB relapse after treatment.

Jensen advocates for a simple, inexpensive, and as yet unevaluated method of implementing a major education programme for care givers and patients, so that persons with diabetes understand the risks of TB, recognise the symptoms and present to health care services when they think they might have TB. He rightly insists that coordinated planning and service delivery across communicable and non-communicable disease programmes is now imperative-“This needs to happen at different levels of the health system- national, district and city level. We also need to invest in human resources so that health workers are able to deliver integrated care for both TB and diabetes”.

“Addressing TB and diabetes in an integrated way will challenge health systems, partly because the conventional approach is for infectious diseases and chronic illnesses to be seen as two different types of health challenges. There is little interaction between infectious disease experts and NCD experts. So part of the challenge will be to break down barriers and to open communication among different groups of public health experts,” says Jensen.